<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>发微博</title>
    <style>
        *{
            margin: 0px;
            padding: 0px;
            list-style: none;
        }
        textarea{
            width: 800px;
            margin:10px auto;
            display: block;
            resize: none;
            outline: none;
        }
        button{
            width: 800px;
            margin:10px auto;
            display: block;
            background:rgb(55, 201, 79);
            border: none;
            cursor: pointer;
            line-height: 40px;
            color:rgb(187, 65, 65);
        }
        ul{
            width: 800px;
            margin:10px auto;
            display: block;
        }
        li{
            background:blueviolet;
            padding:10px;
            margin-bottom: 10px;
            position: relative;
        }
        span{
            position: absolute;
            right: -5px;
            top:-5px;
            cursor: pointer;
        }
    </style>
</head>
<body>
    <textarea name="" id="txt" cols="30" rows="10"></textarea>
<button id="btn">发布微博</button>
<ul id="con">
    <li>
        使命高于一切
        <p>18-09-01·20-09-01</p>
        <span onclick="del(this)">X</span>
    </li> 
</ul>
<script>
    var con=document.getElementById('con')
    var txt=document.getElementById('txt')
    var btn=document.getElementById('btn')
    btn.onclick=function(){
        
         if(txt.value==''){
            alert('请这位帅哥美女输入内容')
        }else{
            var tag=document.createElement('li');
        tag.innerHTML=`${txt.value}
        <p>2021-06-10</p>
        <span onclick="del(this)">X</span>`;
        con.appendChild(tag)
        txt.value='';
         }
    }
    
    function del(a){
        
        a.parentNode.parentNode.removeChild(a.parentNode)
    }
</script>
</body>
</html>